Research tracking the health and happiness of the UK's children

Tag Archives: Sleep

The very best of sleep medicine and research is being presented at the World Sleep Congress in Prague this week. Among that research are findings from work by Child of our Time Editor, Professor Yvonne Kelly and colleagues at the ESRC International Centre for Lifecourse Studies. They have been trying to find out what it is about sleep that matters most when it comes to giving children the best possible start in life. Here Yvonne explains what they have found to date and why regular bedtimes are key to a healthy happy childhood.

What happens in the early years has profound implications for what happens later on in life. Thousands of research papers, many of them using the wonderful rich data in the British Birth Cohort studies, have documented the enduring impacts of the way we live our lives as children on how we fare later on. Children who get a poor start in life are much more likely to experience poor outcomes as adults, whether that’s to do with poor health or their ability to enjoy work and family life later on.

So what has all that got to do with getting enough sleep as a toddler you might ask? Well our research shows it is one of a number of important factors related to getting children off to the best possible start in life and here’s why.

Recommended sleep

The National Sleep Foundation recommends that toddlers should get around 11 to 14 hours sleep every day. For 3-5 year-olds, the recommendation is 10-13 hours and it suggests 9-11 hours for children once they’re at primary school. But is it all about the number of hours sleep children get, or is there more to it than that? Those are the questions we have been addressing in our research into children’s sleep and how it ties in with how they get on at home and at school across the first decade of their life.

Digging into one of those studies mentioned earlier, the Millennium Cohort Study, which has followed the lives of some 20,000 children since the turn of the century, we found that it’s not just the number of hours a child sleeps that matters, but also having consistent or regular bedtimes.

First we looked at the relationship between regular and irregular bedtimes and how the children got on in a range of cognitive tests. The results were striking. Children with irregular bedtimes had lower scores on maths, reading and spatial awareness tests.

Parents who took part in the MCS were asked whether their children went to bed at a regular time on weekdays. Those who answered “always” or “usually” were put in the regular bedtime group, while those who answered “sometimes” or “never” were put in the irregular bedtime group.

Interestingly, the time that children went to bed had little or no effect on their basic number skills, and ability to work with shapes. But having no set bedtime often led to lower scores, with effects particularly pronounced at age three and the greatest dip in test results seen in girls who had no set bedtime throughout their early life.

The key to understanding all this is circadian rhythms. If I travel from London to New York, when I get to there I’m likely to be slightly ragged because jet lag is not only going to harm my cognitive abilities, but also my appetite and emotions. That’s for me, an adult. If I bring one of my children with me and I want them to do well at a maths test having just jumped across time zones, they will struggle even more than I will. The body is an instrument, and a child’s is especially prone to getting out of tune.

The same thing happens when children go to bed at 8 p.m. one night, 10 p.m. the next and 7 p.m. another — we sometimes call this a “social jet lag effect.” Without ever getting on a plane, a child’s bodily systems get shuffled through time zones and their circadian rhythms and hormonal systems take a hit as a result.

Bedtimes and behaviour

At age 7, according to parents and teachers, children in the MCS who had irregular bedtimes were considerably more likely to have behaviour problems than their peers who had a regular bedtime. In addition, the longer a child had been able to go to bed at different times each night, the worse his or her behaviour problems were. In other words the problems accumulated through childhood.

One really important piece of good news was that we found that those negative effects appeared to be reversible, so children who changed from not having to having regular bedtimes showed improvements in their behaviour. There seems to be a clear message here that it’s never too late to help children back onto a positive path and a small change could make a big difference to how well they get on. Of course, the reverse was also true so the behaviour of children with a regular bedtime who switched to an irregular one, worsened.

Bedtimes and obesity

In a follow up study, which looked at the impact of routines including bedtimes on obesity, we reported that children with irregular bedtimes were more likely to be overweight and have lower self-esteem and satisfaction with their bodies.

In fact, of all the routines we studied, an inconsistent bedtime was most strongly associated with the risk of obesity, supporting other recent findings which showed that young children who skipped breakfast and went to bed at irregular times were more likely to be obese at age 11.

Even children who ‘usually’ had a regular bedtime were 20 per cent more likely to be obese than those who ‘always’ went to bed at around the same time.

So we have a body of robust evidence now that shows very clearly that regular bedtimes really matter when it comes to a child’s health and development over that important first decade of their life.

Providing that evidence in the form of advice to parents and all those caring for young children alongside recommended hours of sleep could make a real difference, helping protect our children from ‘social jet-lag’ and getting them off to a flying start instead.

There have been numerous reports in recent months of a growing crisis in children and young people’s mental health. From increased suicide attempts and incidents of self-harm to reports of a complete lack of appropriate services, it’s said that young people are facing unprecedented social pressures and that society’s response has been inadequate. When it comes to trends over time in the mental wellbeing of young people, the evidence to date is conflicting. Meanwhile, new research by Andy Ross and colleagues at the ESRC International Centre for Lifecourse Studies at UCL shows that the way we look at those trends may be masking an important story that could help those trying to tackle the problem to identify those most at risk of serious mental health problems.

There are few more high profile health issues at the moment than the mental health crisis among young people. The younger Royals may have helped raise public awareness about the need for more open conversations, but they agree the job is far from done. From a policy perspective, there are pledges of mental health legislation reform in the Queen’s Speech promises from Teresa May that her Government will “ensure that mental health is prioritised in the NHS in England”. But a recent report from NHS Providers says the government’s commitment to parity of esteem between mental and physical health services is being undermined by a failure to ensure funding increases reach the frontline.

Having a full and clear grasp of the scale of the problem and how young people’s mental wellbeing is changing over time will be key to any policies that may be developed to tackle it.

One of the main problems facing those trying to better understand the extent of the problem and whether the situation is getting better or worse, is that the evidence presented to date has been somewhat conflicting and, in some cases, doesn’t give the whole picture.

Some research has shown young people’s mental health deteriorating in the nineties and then stabilising and slightly improving in the early 2000s, whilst other work has evidenced a steady decline. Findings have also been different depending on whether it is teachers, parents or the young person themselves who are asked to report the symptoms.

Trends over time

We wanted to see whether we could add to and improve on the available evidence and show a more nuanced picture of mental health problems among young people by looking at trends over time, not just in respect of average levels of mental health, but also across the spectrum in levels of mental health. In simple terms, we were looking to see whether there were increases in the number of young people with unusually low levels of mental distress at the same time as increases in the numbers of those with very high levels of distress over an 18-year period.

Making use of information collected between 1991-2008 from more than 6,000 young people who took part in the British Household Panel Survey, we looked closely at their self-reported psychological distress. Once a year, young people between the ages of 16-24, were asked whether and how often, for example, they had experienced the loss of sleep through worry, a loss of confidence, felt constantly under strain, unhappy or depressed. They were also asked about positive symptoms such as their ability to concentrate and face up to their problems.

All this information was then combined to create an overall psychological distress score on a scale of 0-36, with high scores indicating high levels of psychological distress.

When we looked at the average psychological distress scores for young women in the study, we saw a small but significant increase over the 18-year period, indicating that, for this group, the situation worsened – in other words, their mental health deteriorated.

No increase was detected in the average scores for young men, which could be interpreted as a sign that levels of mental health among this group remained fairly stable.

At every time point, scores for women were worse than they were for men and this gap increased over time.

A story of polarisation

When we drilled deeper into the scores, however, the story changed a little. For young women there was a very clear and consistent increase in high and very high scores, following the overall increase in average scores mentioned above. The prevalence of those with high scores (17 and higher) increased from 12.8 per cent in 1991 to 18.8 per cent in 2008, and the prevalence of those with veryhigh scores (20 and higher) from 6.6 per cent to 11.9 per cent. At the same time, however, there was also a small increase in the prevalence of those with scores much lower than average (5 and lower) from 10.6 per cent to 13.0 per cent.

It seems that when we move beyond looking only at average mental health scores over time, we identify two very different yet concurrent pictures of young women’s mental health. An increase in the number of young women presenting very poor levels of psychological distress, whilst at the same time an increase in young women with far better levels of mental health than average. In other words, over time, the mental wellbeing of young women appears to have become polarised.

Previously, our findings suggested that levels of mental health among young men had remained stable. However, when we look at both low and high scores over time, we find a very clear and consistent increase in low and very low scores, suggesting an overall improvement in levels of mental health among young men.

The prevalence of those with low and very low scores increased from 8.1 per cent to 15.6 per cent and from 2.1 per cent to 5.9 per cent respectively. At the other end of the scale however, whilst there was an increase in prevalence of those with high and very high scores, this increase was too small for us to consider it statistically significant[1]. Nevertheless, by considering trends at both ends of the spectrum we identified an improvement in young men’s mental health, which was otherwise ‘hidden’ when we only looked at average scores over time.

Although our study did not delve deeply into the backgrounds and circumstances of the young people with low and high scores, we did look at income levels to see if increasing levels of inequality might explain what we were seeing. It doesn’t appear to.

What we did find was evidence to support earlier research, which suggests that girls might feel increased pressure to achieve academically, which could contribute to increased levels of psychological distress.

Doing it for themselves

We are yet to explore causes for these trends, however one area that remains significantly under researched is the idea that we are becoming a more individualistic society, in which there are increased expectations placed on young people and an emphasis on them “doing it for themselves”. This includes increased pressure to take responsibility not just for one’s successes, but also for one’s failures, previously thought of as misfortunes, such as unemployment, illness and addiction. It is easy to imagine how the personalising of one’s failings could contribute to a young person’s poor mental health, or how they might develop a fear of failure even.

On the other hand, taking more responsibility for their own destiny could be empowering when things go well, boosting their self-esteem and confidence.

Evidence of polarising trends in young women’s mental health could be the first step in linking time trends to the sort of cultural and societal individualization that is being increasingly talked about amongst those concerned with the health and wellbeing of the UK’s young people.

For young women, continuing gender inequalities (some legislative, some cultural), which serve to frustrate women’s dreams of self-realisation, might also help to explain the differences in poor levels of mental health in particular that we see between them and young men.

By 2020, the NHS has promised that 70,000 more young people will be able to access services for their mental health problems. Robust evidence on trends and how the story of young people’s mental health is changing over time will be key to ensuring those services are provided effectively and efficiently.